Automatic Ammonium Analyzer

Abstract

For an automated determination of a ammonia nitrogen content in a liquid sample, an analyzer and method are provided. The following steps are performed by the method: generating a reagent solution by electrolysis that contains hypochlorite ions to be added to the liquid sample, and feeding the reagent solution into the liquid sample; feeding at least one other reagent solution into the liquid sample and generating a reaction mixture from the reagent solutions and the liquid sample; sensing a measuring signal with a photometric measuring device that correlates with a measuring variable of the reaction mixture; and on the basis of the measuring signal, determining a measuring value for the ammonia nitrogen content with an electronic control device.

1 - 19 . (canceled) 
     
     
         20 . A method for an automated determination of the ammonia nitrogen content in a liquid sample, comprising the steps of:
 generating a reagent solution by electrolysis that contains hypochlorite ions to be added to the liquid sample, and feeding the reagent solution into the liquid sample;   feeding at least one other reagent solution into the liquid sample and forming a reaction mixture from the reagent solutions and the liquid sample;   sensing a measuring signal of a photometric measuring device that correlates with a measuring variable of the reaction mixture; and   determining a measuring value for the ammonia nitrogen content with an electronic control device, on the basis of the measuring signal.   
     
     
         21 . The method according to  claim 20 , wherein:
 the reagent solution containing hypochlorite ions is generated by electrolysis of a salt solution, said salt solution being one of:   an alkaline, and a sodium chloride or potassium chloride solution.   
     
     
         22 . The method according to  claim 20 , wherein:
 a solution comprising a phenol compound, which is one of: a thymol or salicylate solution, and a pentacyanonitrosylferrate solution (nitroprusside) which is fed to the liquid sample as further reagent solutions for forming the reaction mixture.   
     
     
         23 . The method according to  claim 20 , wherein:
 the photometric measuring device introduces a measuring radiation into the reaction mixture and receives the intensity of the measuring radiation after passing through the reaction mixture, and provides an electrical measuring system that depends on the intensity received.   
     
     
         24 . The method according to  claim 20 , wherein:
 a hypochlorite amount is produced that is sufficient for exactly one detection reaction.   
     
     
         25 . The method according to  claim 20 , wherein:
 a hypochlorite amount is produced that is sufficient for several detection reactions.   
     
     
         26 . An analyzer for determining an ammonia nitrogen content in a liquid sample, comprising:
 an electrolysis device for generating a reagent solution containing hypochlorite ions to be fed into the liquid sample;   at least one liquid tank containing a reagent solution to be fed into the liquid sample, which contains one of: a phenol compound and/or pentacyanonitrosylferrate;   at least one feed and dosing device that serves to dose and feed the reagent solutions into the liquid sample to form a reaction mixture from the liquid sample and the reagent solutions;   a photometric measuring device to provide a measuring signal correlated to a measuring variable of the reaction mixture; and   a control device that is equipped to control said electrolysis device, said feed and dosing device and said photometric measuring device, and to determine a measuring value for the ammonia nitrogen content based on the measuring signal provided by said measuring device.   
     
     
         27 . The analyzer according to  claim 26 , further comprising:
 a first liquid tank containing a reagent solution comprising a phenol compound, which contains one of: a thymol or salicylate solution; and   a second liquid tank containing a pentacyanonitrosylferrate reagent solution.   
     
     
         28 . The analyzer according to  claim 26 , wherein:
 the measuring signal from said photometric measuring device correlates with an absorption or extinction of a measuring radiation passing through the reaction mixture.   
     
     
         29 . The analyzer according to  claim 26 , wherein:
 said electrolysis device is designed to electrolytically generate the reagent solution containing hypochlorite ions from an alkaline salt solution, which may be from an alkaline NaCl solution.   
     
     
         30 . The analyzer according to  claim 26 , wherein:
 said electrolysis device includes an anode and a cathode that may be connected at least temporarily to apply a DC voltage between the anode and the cathode with a constant current source.   
     
     
         31 . The analyzer according to  claim 30 , wherein:
 the cathode is designed as an oxygen-consuming electrode.   
     
     
         32 . The analyzer according to  claim 30 , wherein:
 said electrolysis device contains an electrolysis cell with a feed line and a discharge line;   the internal part of said electrolysis cell is in contact with at least one surface of the anode and the cathode.   
     
     
         33 . The analyzer according to  claim 32 , wherein:
 said at least one feed and dosing device of the analyzer is designed to supply liquid removed from said electrolysis cell to the liquid sample.   
     
     
         34 . The analyzer according to  claim 32 , wherein:
 said cathode is designed as a flow cell.   
     
     
         35 . The analyzer according to  claim 32 , wherein:
 said electrolysis cell has a hydrogen separation chamber arranged above the space in said electrolysis cell filled with liquid during operation, with the former being linked to a valve device of the analyzer via a gas line, in order to allow the discharge of hydrogen amassing in the hydrogen separation chamber via a gas discharge line, which may be different from the gas feed line.   
     
     
         36 . The analyzer according to  claim 32 , wherein:
 said electrolysis cell has an anode chamber in contact with the anode and a cathode chamber in contact with the cathode; and   said anode chamber is separated from said cathode chamber via a diaphragm.   
     
     
         37 . An analyzer according to  claim 26 , wherein:
 said electrolysis device is linked via a feed line with a liquid tank that contains a preferably alkaline salt solution, which may be: a salt solution containing sodium chloride and/or potassium chloride.   
     
     
         38 . An analyzer according to  claim 26 , wherein:
 said electrolysis device is preferably designed as a module that can be separated from the other components of the analyzer device.